Question

以下代码不起作用。

def set_view_counts(self):
    """
    Initializes the view counts for all of the Concept objects in the ConceptModel. See Concept for a
    description of why this parameter is optional.
    """
    for node in self.nodes():
        p = PageviewsClient().article_views("en.wikipedia", [node.concept.replace(' ', '_')])
        p = [p[key][node.concept.replace(' ', '_')] for key in p.keys()]
        p = int(sum([daily_view_count for daily_view_count in p if daily_view_count])/len(p))
        node.properties['view_count'] = p

当我查看node.properties词典的内容时，我发现4560, 4560, 4560, 4560。

以下代码可以。

def set_view_counts(self):
    """
    Initializes the view counts for all of the Concept objects in the ConceptModel. See Concept for a
    description of why this parameter is optional.
    """
    for node in self.nodes():
        p = PageviewsClient().article_views("en.wikipedia", [node.concept.replace(' ', '_')])
        p = [p[key][node.concept.replace(' ', '_')] for key in p.keys()]
        p = int(sum([daily_view_count for daily_view_count in p if daily_view_count])/len(p))
        node.properties = p

当我查看属性时，我找到11252, 7367, 3337, 4560。

这里发生了什么？

Answer 1

我们需要看到更多你的代码，但是我在你的函数中添加了一些内容，猜测你可以编写什么来重现你的bug：

有了这个，我得到：

class Node:
    def __init__(self, props={}):
        self.properties = props

class G:
    def __init__(self):
        self.n = [Node(), Node(), Node(), Node()]

    def nodes(self):
        return self.n

    def set_view_counts(self):
        p = 0
        for node in self.nodes():
            node.properties['view_count'] = p
            p = p + 1

    def __repr__(self):
        r = ''
        for node in self.nodes():
            r += node.properties.__repr__()
        return r

g = G()
g.set_view_counts()
print g

这是因为{'view_count': 3}{'view_count': 3}{'view_count': 3}{'view_count': 3}中props参数的默认值。所有Node.__init__共享相同的dict（用作默认值的Nodes。通过删除默认值来解决此问题。

将项目分配给对象的字典

1 个答案: